Using a single ASCII file
You can define relationships by specifying the common parts (keys) of two levels, and the related level must be specified for each separate level. Levels that are related to other levels are always sequential, but levels without relationships with other files are always iterative.
Example
In case of a Single file layout, there is one file with five levels and a unique level identifier per level:
| Level | File | Level Identifier |
|---|---|---|
| -1 | orders | ENV |
| -2 | orders | MISC |
| -3 | orders | HEADER |
| -4 | orders | ADDRES |
| -5 | orders | LINE |
You cannot refer to a related (parent) level file with a higher level number than that of the current level.